What a great question! Growing up, my dad worked as a butcher at a slaughterhouse. He would get the brains out of the cow heads and use them for bait. He even made what he called brain cups out of a cut in half baby bottle with a bobber stapled to the bottom of it and a hole drilled into the top side for the fishing line to slide through along with a bead and split shot. You drop your baited hook into the cup and cast away. The cup would hit the water and turn bobber side up and the bait would slowly sink to the bottom. You think chicken liver is easy to throw off your hook, brains were worse. You could also tie a small piece of rubber band at different depths on your line to fish on top. Once the piece of rubber band came to the bead, it would stop sinking.
Anyway, that brings back a lot of great memories of fishing with my dad at pay lakes. We were the only ones who had beef brains and would slay the catfish while everyone else was catching nothing. Other fishermen would holler out and ask what we were using as bait, we would say m&m's. Lol
Catalpa worms, night crawlers, chicken soaked in cherry kool-aid, chicken livers, beef spleens, eels, green worms, minnows, bluegils and wheatie balls are some more good baits.
And don't forget, a good spit of chewing tobacco juice, sweet oil, or anything smelly put on your bait always helps.
Thanks for the question, I enjoyed answering it. It brought back a lot of fond memories.
May God Bless You!